What is the breath-test machine most commonly used for determining bac is?

The breath-test machine most commonly used for determining Blood Alcohol Content (BAC) is known as the Breathalyzer. It is a hand-held device that measures the amount of alcohol present in a person's breath. The Breathalyzer works by analyzing an individual's deep-lung air, which is assumed to be directly proportional to the alcohol level in their bloodstream. The machine does this by reacting to the presence of alcohol with a chemical reaction that produces a small electrical current. The magnitude of the current produced is proportional to the amount of alcohol present in the breath. The Breathalyzer is calibrated to provide a BAC reading based on the amount of current produced, and it is used by law enforcement agencies to establish whether a driver is legally impaired. The accuracy of the Breathalyzer depends on several factors, including the calibration of the device, the presence of other substances in the breath, and the time elapsed since the person last consumed alcohol. Despite its widespread use, the Breathalyzer has been controversial due to questions about its reliability and effectiveness.